My Little Pony: Equestria Girls-Crystal problem

After the message, in the human world, about 5-10 minutes before the scheduled meeting, Cadance, Celestia, Luna and Mane 7(Sunset and friends) are waiting outside the gateway.

Prior to receiving the message, Sunset and her friends were helping the other students organise the Halloween party.

While they were waiting, Dean Luna asked Mane 7 who Sombra was after the three adult women were told who was going to help them.

"Well, we haven't met him in person yet," Sunset began to explain, "but, from what Princess Twilight has told us, we know that he was once a tyrant king in the Crystal Empire, and now he is the beloved King of the Crystal Empire!"

"Wait a minute..., he used to be a tyrant, but now he's a beloved king?" asked Luna, puzzled, "May I ask what this guy did to go from being a scum of the past to a beloved king?"

"Essentially, he risked his life to protect the citizens of the Crystal Empire from a shadow thing attacking from another world in a war he almost gave his life to end, which, if it had spread any further, would have endangered even us."

"Who set it off, what does this guy have to do with it, and why would it threaten us?" asked Celestia curiously.

Here they launched into the storytelling, explaining to the adults in broad outline the events of the war, directly related to Sombra's exploits, while also answering questions that arose in the meantime.

For example, they explained that they were unable to contact Twilight because she had left the diary in her castle when they travelled to the Empire, and for security reasons she had disconnected the log from the crystal mirror, so they were unable to pass through the portal.

Plus Twilight forgot about this world because of the events in the Empire.

They also answered the other question, which was why would this threaten them.

Basically because if the war had extended beyond the Crystal Empire and the shadow leader (leader of the shadow creatures)found the crystal mirror, then his destruction would have continued in this world as well.

"So this guy's a hero! ... - Luna made her point, -But then what drove him to become a tyrant?"

"Because of his terrible youth! ... -sighs Rarity sadly, whose long purple hair and blue blazer, slightly adorned with gems, glistened in the bright sunshine after she took her hand out of the pocket of her blue jeans, with which she had put on dark blue high heels.

"Suffice it to say that he was physically and emotionally abused by many, including his parents!" she shuddered as she recalled what Twilight had told her about the things her friends, her brother, and her sister-in-law had seen in those horrible nightmares.

"Poor guy! ... -Cadance pitied her, -But what made them treat him so?"

"As I understand it," Sunset added, "it was forbidden in those days, for it was thought that one who used such magic could only be evil!" she sighed, and then her sadness turned into a faint smile, "But she taught many that dark magic was only a lil' magic... And according to Twilight's writing," Sunset added, "King Sombra can, because of his dark magic, determine the names and uses of all... well, almost all the crystals."

"But, if he transforms," Celestia reminded them, "he won't lose his ability, since we humans can't use magic. That is, with your exception."

"Maybe everyone can use magic! ... - Twilight Sparkle (Sci-twi) began her hypothesis while adjusting her glasses, -Because probably all you need is some sort of intermediary device for someone who can't use magic naturally! -pointing to the necklaces with the logo around her neck, then to the necklaces around her friends' necks.

"Oh, right... I forgot about those," Celestia remembered the crystals as she slapped herself across the face, remembering back to the events in the Everfree forest.

"Add to that," Sunset began her explanation, "Mister Sombra's crystal expertise... ," she interrupted her sentence as she saw the familiar glint of a side of the statue's pedestal, and then suddenly a man fell out of it, falling to the pavement, slightly unconscious, "I think Mister Sombra has arrived!" she announced with a smile.